Hydraulics and flow control concepts are utilized in positioning and lifting applications. Hydraulics and flow control are often segmented based on the operational requirements and pressure utilized for a given application. For example, in many heavy lifting applications the hydraulics and flow controls are designed to work in high pressure and high flow configurations. These applications include operating pressures in excess of one-thousand pounds per square inch (>1000 psi) and flow rates measured in gallons per minutes (G/min). In high pressure and high flow applications, the actuators are typically constructed to provide the mechanical strength calculated to withstand the stresses and forces to which they may be subjected. In another example, biomedical devices and other precision, low force applications are designed to work in low pressure and low flow configurations. These low flow applications include operating pressures at pressures below one hundred pounds per square inch (<100 psi) and flow rates measured in milliliters per second (ml/sec). The actuators in low flow, low pressure applications are typically precision and/or miniature devices capable of providing a minimal force.
The limitations inherent in both the high pressure/high flow and low pressure/low flow applications effect the development of robotic and/or prosthetic appendages such as robotic and/or prosthetic fingers and/or hands. For example, a robotics and/or prosthetic appendage configured for a high pressure/high flow application to generate large forces and/or provide a quick response may be bulky and be difficult to precisely control. Alternatively, a robotics and/or prosthetic appendage configured for a low pressure/low flow application to provide precision control may be slow to respond and unable to generate large forces. Accordingly, actuators, valves, controls and devices that address these limitations are desirable.